1. Field of the Invention
This invention relates to an outboard motor control system.
2. Description of the Related Art
A trend in outboard motor control systems in recent years is the emergence of drive-by-wire (DBW) systems that use actuators for one or more control operations among steering the outboard motor, changing its shift position, and regulating the speed of its internal combustion engine. The system comprises at least one actuator, a navigation unit for producing actuator drive commands in accordance with control input from the boat operator, and a control unit for controlling the operation of the actuator based on the output of the navigation unit.
As described in Japanese Laid-Open Patent Application No. 2004-52697 (particularly paragraphs 0023 to 0025), for example, boats are commonly equipped with two or more outboard motors mounted side-by-side in what is called a “multiple outboard motor installation.” This reference is directed to enhance convenience by making it possible to start the engines of all installed outboard motors by operation of a single switch.
When multiple navigation units are provided, they are connected to the control units of the outboard motors in a one-to-one relationship. Therefore, if the navigation units should produce markedly different outputs owing to different control inputs, the control will become unstable because the control units cannot determine which navigation unit output should be given priority.